London: Britain's interior minister says the security firm G4S repeatedly assured the government it would exceed its targets for recruiting Olympic staff and only admitted last week that it could not meet the terms of its contract.

Home Secretary Theresa May said on Tuesday that G4S had "repeatedly assured us that they would overshoot their target."

Britain is calling in 3,500 extra troops to cover the positions G4S could not fill.

G4S chairman John Connolly says senior managers could lose their jobs over the fiasco.

The company said on Tuesday its loss on the contract would range between 35 million to 50 million pounds (USD 54 million-USD 78 million) in this financial year.

A loss of 50 million pounds is about 12-13 percent of the company's annual profit, analysts calculated.